Such an electronic system is, for instance, a smart card. In general, a smart card is any pocket-sized card with an embedded integrated circuit that comprises a microcontroller which can process information. Smart cards can be categorized in accordance with different criteria. Particularly, smart cards can be categorized as memory-chip cards that comprise a relatively simple logic and as processor-chip cards that comprise, for instance, an operation system. Particularly processor-chip cards can receive an input signal which is processed, by way of an integrated circuit application, and deliver an output signal. Generally, smart cards can be contactless or contact smart cards, or can be a combination of both.
Smart cards may include a chip on their fronts. The chip may be made from gold and has a size of approximately 1 cm by 1 cm. The contact smart card may communicate with a reader. When inserted into the reader, electrical connectors of the reader contact the chip for reading information from and writing information back to the smart card. Since normally the smart card does not include a battery, energy is supplied to the contact chip card by the reader. Contact smart cards are, for instance, standardized by ISO/IEC 7816 or ISO/IEC 7810.
In a contactless smart card, the integrated circuit communicates with the reader in a contactless manner, for instance through Radio-frequency identification (RFID). Contactless smart cards are, for instance, standardized by ISO/IEC 14443 or ISO 15693. Contactless smart cards are also known as transponders which may or may not include an active energy source, such as a battery. Transponders not having a battery are also known as passive transponders and transponders comprising a battery are known as active transponders.
International application for patent No. 94/20929 discloses a smart card that comprises an electronic data memory, an interface means connected to the data memory, to allow access to a reader, and a data display operable to display information indicative of the contents of the data memory.
Smart cards may be used, inter alia, as banking cards, transportation ticketing, loyalty cards, or e-passports. Because of this, a relatively high security level against fraudulent tampering of the card must be assured. While the microcontroller of the smart card usually provides a secure environment, the integration of a display into the smart card and particularly information exchange between the microcontroller and a display driver configured to drive the display potentially increases the danger of fraud and tampering of the smart card.